What is the difference between Java Persistence Query Language (JPQL) and Hibernate Query Language (HQL)?

JPQL (Java Persistence Query Language) is a standard query language defined by the JPA (Java Persistence API) specification. It is designed to work with objects and their relationships in terms of entities, not database tables. JPQL is independent of any specific ORM implementation.

HQL (Hibernate Query Language) is Hibernate's own query language, which is similar to JPQL but includes extensions and additional features specific to Hibernate.

Main differences:

• JPQL is a standard supported by various JPA providers.
• HQL is an extension of JPQL with additional functions specific to Hibernate.

In most cases, JPQL queries work in Hibernate as well, but if Hibernate-specific features are needed, HQL is used.